Multistage turbine.



E. JOSSE & P. GHRIS'T'LEIN.

MULTISTAGE TURBINE. APPLICATION FILED APR.1 5, 1911.

Patented May 20, 1913.

Um-ran STATES PATENT oFFicn.

' MULTISTAGE TUR BINE Specificationiof Letters Patent.

Patented May20, 1913.

Application ,filea'a rn 15, 1911. serial no. 621,417.

To all "whom it may cont/em:

Be it known that we, EMIL' Jesse and Rim.- Crtms'rLnnN, sub ects of the German Enipeior, esidiiig at 157 Uhlandsti asse, Berlin, and at 1 Guerickestrasse, Ohar lot'tenburg, Germany, respectively, have invented certain new and useful Improvements in Multistage'Steam orGas Turbines with Axial or Radial Admission; and we do hereby declare the following to be a full, clear,'and exactdescription of the invention, such as will. en-

able others skilled in the art to which it uppertainsto make and use the same. It has been usual with multi stage imuls'e r actionfor combined turbines in- 7 7 which the steam admission wasj'efiected by ordinary passages wlth parallel walls, to so adjust the number of stages and the dimensi'ons of the rotors, that the steam velocity produced at each step does-not exceed the maximum of about 150 m. (the so-called critical velocity) owing to the beliefthat in. this way loss by friction in theconducting and running blades was kept as low as possible.

The ,tiew was held that the loss by friction in the turbine elements increased approximately as the third'power of the velocity of the steam fiowingthrough the engine. The efficiency curve based upon the foregoing issuniption is shown at Figure l of the drawing in which the abscissa represents the steam velocity while the ordinates represent he etficiency shown by a. Accordin to the uncut hypothesis the maximum etdiciency 3; obtained when the steam velocity is zero.

Experiments made by the inventors have demonstrated the fact that the loss of energy occasioned by the movement of the steam through the conducting passages and the fiifivanes of the rotor, that is.the loss of flow,

been supposed.

does not in fact correspond with the curve a, but with the curve?) Fig. 1, in such a way that when the velocity is small considerably greater losses are present th'an has hitherto Then'eason of this phenomenonis that a giuatcr-density of steam corresponds to-a' small velocity and that thelosses due to the greater density are relatively great in spite of the lowvelocity. Again, as experiment has shown, the efiiciency curve 6 possesses a cert-am maximum which in the case of an ordinary conducting apparatus with parallel walls is far below the so called critical velocity and moreover with the conce tion of the critical velocity- (about 450 In.) iithertoaccepted, to pass this velocity meant'extreme losses on account of the production of vibration, etc. The con,-,

sequence has been that hitherto impulse and reaction turbines or combined nnpulsc and reaction turbines have been provided with I At Fig. 2 of the drawing is shown by way of example a combination multi-stage impulse turbine made according to the invention. Fig. 3 of the drawing shows a pure reaction turbine. Fig i shows a radial admission turbine with nozzles and blades moving in oppositeidirections. Fig. 5 shows a combined impulse and reaction turbine.

At Fig. 2, l is a Curtis wheel (with pressure stages and velocity stages), 2 shows the rotors for three separate pressure stages, as an example, no velocity-stages being shown. The three stages workaccording to the principles of this invention with practically the maximum elliciency and that in spite of the considerable excess over the critical velocity at each stage. i

' The result of the increased rate of motion of the fluid at the individual pressure stages and of the consequently lessened number of such stages,'is that, besides increased eliicicn y other advantages are obtained, namely :A decreased length of the whole turbine, in consequence of the reduced number of rotors. A smaller expenditure of mawith consequent reduction in cost or use of better material. \Vith equal admission passages a considerably increased output from the turbine is obtained up to 100%.

\Vhile retaining the maximum length of the blades, it is not necessary for controlling the volume of steam in the low pressure stages to increase the exit angles, a construe tion which would otherwise cause a reduction of efliciency at these stages.

iccording to Fig. 3 of the drawing which shows; a -.p ur.e -reaotionturbine built for the greatest efliciency, 3 iS. the drum with several rings'of blades and withfull admission passages from the first stage onward, 4 are the conducting passages fitted with parallel walls; In the method of carrying out the invention-shown at Fig. 4:, 5 and 6 are the oppositely moving rotors with radial admission,

the'channels' having parallelwalls so proportionedthat as the working fluid passes.

through, the critical velocity-is considerably exceeded byabout 10% to 60%. 7 is the hollow shaft through which the'steam admission is effected. 8'is a solid shaft for the other rotor 6.

In the'method of Carrying the invention into eflect'shown at Fig. 5, a combined impulse and reaction turbine is shown with a rotor 9 belonging to the first high pressure stage and a reactiondrum 10, the first ring of blades-0n which, 11, belongs to the high pressure stage, while the further ring of' blades 12 belongs to the reaction turbine.

In addition to the advantages already mentioned, multifstage gas or steam reac-' tion turbines made according to the present invention possessfspecial advanta es.

Reaction turbines as constructed up to the present are notr'suitable for use with high .degrees of vacuum, as with the velocity at present in use of the steam blowing through the engine 150 m. to 350m.) conducting and rotor blades of the necessary height cannot be employed. With .the present invention the required result'can be obtained. without any difiiculty, in consequence of the cons-iderably' greater welocity. This'for example is very important with steam exhaust tur bines. 40 For instance, if a thre'e thou'sand- K;

turbine is built according tothe'preferred form" of thisinvention, as an impulse turbine, it requires about slxstages and, -'there-' fore, six separate rotors each with its ring 45 of blades and five carefully made heavy se comprising. plurality of rotors havingfi blades;lpressurefluid admitting means :hav-

ing para llel walls," said. fluid admitting -meansand saidrotors being so proportioned ythat'at each stage a velocity exceeding 450 m. per second is attained whereby the loss of flow in the passages'between the fixed and movable blades is reduced.

In testimony whereof, we afiix our signatures, in presence of two witnesses. EMI-LJOSSE.

PAUL CHRISTLEIN. Witnesses HENRY Hnsrnn, oLnnimn HAUPT. 

